New! View global litigation for patent families

US4329160A - Suppression of COS formation in molecular sieve purification of hydrocarbon gas streams - Google Patents

Suppression of COS formation in molecular sieve purification of hydrocarbon gas streams Download PDF

Info

Publication number
US4329160A
US4329160A US05935757 US93575778A US4329160A US 4329160 A US4329160 A US 4329160A US 05935757 US05935757 US 05935757 US 93575778 A US93575778 A US 93575778A US 4329160 A US4329160 A US 4329160A
Authority
US
Grant status
Grant
Patent type
Prior art keywords
gas
bed
hydrocarbon
molecular
water
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US05935757
Inventor
John D. Sherman
Arthur T. Katsaros
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Katalistiks International Inc
UOP LLC
Original Assignee
Union Carbide Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Grant date

Links

Images

Classifications

    • BPERFORMING OPERATIONS; TRANSPORTING
    • B01PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01DSEPARATION
    • B01D53/00Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols
    • B01D53/02Separation of gases or vapours; Recovering vapours of volatile solvents from gases; Chemical or biological purification of waste gases, e.g. engine exhaust gases, smoke, fumes, flue gases, aerosols by adsorption, e.g. preparative gas chromatography
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C7/00Purification; Separation; Use of additives
    • C07C7/12Purification; Separation; Use of additives by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers
    • C07C7/13Purification; Separation; Use of additives by adsorption, i.e. purification or separation of hydrocarbons with the aid of solids, e.g. with ion-exchangers by molecular-sieve technique

Abstract

In the process for purifying hydrocarbon gas streams containing hydrogen sulfide and carbon dioxide as impurities by contact thereof with zeolitic molecular sieve adsorbents to selectively adsorb the impurities, the formation of carbonyl sulfide by the zeolite catalyzed reaction of H2 S with CO2 is greatly suppressed by employing as the selective adsorbent certain cation forms of molecular sieve zeolites which contain from 0.7 to 3 weight percent adsorbed water.

Description

RELATED APPLICATIONS

This application is a continuation-in-part of our prior application Ser. No. 836,001 filed Sept. 23, 1977 and now abandoned, which is in turn a continuation of application Ser. No. 486,638, filed July 8, 1974 and now abandoned.

The present invention relates in general to the purification of hydrocarbon gas streams containing as impurities H2 S and CO2, and more particularly to process whereby H2 S is selectively adsorbed from such hydrocarbon gas streams using zeolitic molecular sieves having minimal catalytic activity with respect to reaction between H2 S and CO2 to form COS.

The gas phase treatments of hydrocarbon feedstocks, particularly natural gas, to remove H2 S and other impurities by selective adsorption and absorption techniques is well known. Natural gas, for example, commonly contains water, hydrogen sulfide, carbon dioxide, plus other sulfur compounds and heavier hydrocarbons in various concentrations depending upon its source. The end use of the natural gas dictates which impurities must be removed and the extent of that removal. When the gas is to be transported by pipeline, there are specifications for its water and corrosive sulfur, as hydrogen sulfide, contents. Transmission and some other end uses do not require removal of carbon dioxide except in those instances where a minimum heating value needs to be met. Natural gas feed to a liquefaction unit requires much more thorough clean-up to protect against solids formation by water and carbon dioxide in the cryogenic equipment.

The selective adsorption character of molecular sieve has been quite ideal for these purifications for the reason that the order of adsorption selectivity is: H2 O>H2 S>CO2 >CH4. Thus when crude natural gas is passed through a molecular sieve adsorbent bed, the impurities adsorb in zones and it is possible to adsorb only the water, or water and H2 S, or H2 O, H2 S and CO2 to any desired extent.

It has been found, however, that when both H2 S and CO2 are present in the feedstock, COS is frequently present in the product gas, i.e., after treatment in a molecular sieve purification unit, in higher concentrations than in the feed. This is apparently due to the fact that the molecular sieve serves as a catalyst for the reaction

H.sub.2 S+CO.sub.2 ⃡COS+H.sub.2 O

and also due to the fact that the COS, once produced in the adsorption bed is not retained therein as an impurity adsorbate because of its low polarity and low boiling point compared with the same properties of the other impurity molecules present.

Accordingly, it is the principal object of the present invention to provide a means to suppress the formation of COS when sweetening hydrocarbon gas streams containing both H2 S and CO2 using molecular sieve adsorbents.

This object, we have found, is accomplished in the cyclic process comprising the steps of the cyclic process comprising the steps of (a) an adsorption purification stroke wherein a hydrocarbon stream containing H2 S and CO2 is contacted in the vapor phase at a temperature of from 60° F. to 120° F. with a zeolitic molecular sieve adsorbent in a fixed bed to selectively adsorb H2 S and a hydrocarbon product is recovered which is substantially free of H2 S; (b) a purge desorption stroke wherein a portion of the substantially H2 S--free hydrocarbon product recovered in step (a) is heated to above 120° F. and passed countercurrently through the adsorption bed to desorb substantially all of the adsorbate molecules selectively adsorbed in step (a) and flush same from the bed; (c) a cool-down stroke wherein the bed is cooled to below 120° F. by the cocurrent purge therethrough of a portion of the substantially H2 -free hydrocarbon recovered in step (a) at a temperature of from 60° F. to 120° F.; the improvement which comprises utilizing as the said molecular sieve adsorbent a crystalline zeolite having a pore diameter of at least 5 Angstroms, at least 45 percent of the framework aluminum atoms thereof being associated with at least one species of alkaline earth metal cation having an atomic number of less than 56, and injecting into said hydrocarbon stream prior to passage through the bed in step (b) a sufficient amount of water vapor to import a substantially uniform adsorbed water loading of from 0.7 to 3.0 weight percent to the molecular sieve adsorbent.

Although the preferred feedstock for treatment in accordance with the present process is CO2 -containing sour natural gas, any hydrocarbon of mixture of hydrocarbons containing H2 S and CO2 which is in the vapor state at a temperature within the range of 60° F. to 120° F. and a pressure of from 200 to 1200 psia and which is less strongly adsorbed than H2 S is suitably treated. The preferred natural gas feedstock contains, in addition to methane, water in any concentration up to saturation, up to 5 mole percent H2 S, from 0.5 to 55 mole percent CO2 and not more than 25 mole percent hydrocarbons having more than one carbon atom. Commonly such hydrocarbon feedstocks will also contain organic sulfur compounds such as mercaptans.

The drawing is a schematic flow diagram showing a three bed process system suitably employed in the practice of the present process.

The molecular sieve zeolite adsorbent can be any naturally occurring or synthetic crystalline zeolite which contains at least 45 equivalent percent beryllium, magnesium, calcium, or strontium cations or mixtures of any two or more of such cations and which has in this cation form a pore diameter of at least 5 Angstroms. The calcium cation forms of zeolite A and zeolite X as defined in U.S. Pat. No. 2,882,243 and U.S. Pat. No. 2,883,244 respectively, have been found to have especially low catalytic activity with respect to the reaction of H2 S and CO2 and are particularly preferred in the present process. Other suitable zeolites include the calcium cation forms of mordenite, chabazite, faujasite and zeolites Y disclosed in U.S. Pat. No. 3,130,007; zeolite T disclosed in U.S. Pat. No. 2,950,952; zeolite L disclosed in U.S. Pat. No. 3,216,789; and zeolite omega disclosed in pending U.S. application Ser. No. 655,318, filed July 24, 1967.

The required water loading on the zeolite adsorbent is readily attained by any conventional means. In cyclic continuous operation in which an adsorbent bed is periodically desorbed by means of a hot purge gas, commonly a portion of the purified product gas, it is convenient to inject water vapor into that purge gas stream in appropriate amount such that after desorption and cool-down of the bed is complete, the requisite water loading remains on the bed.

The following example is illustrative of the present process:

EXAMPLE 1

(a) With reference to the drawing, a natural gas feedstock having the following composition was employed in the process:

______________________________________CH.sub.4       95.     mole %H.sub.2 O      .106    "CO.sub.2       3.      "H.sub.2 S      .006    "______________________________________

In the drawing it is to be understood that each of the three adsorbent beds shown are equivalent and each in turn would, in conventional operation, undergo the steps of adsorption, hot purge desorption and cool-down in preparation for the next cycle of the same three steps. For simplicity, the various valves, manifolds, pumps, etc. ordinarily used in this conventional three-bed type of operation have been omitted. The drawing shows the simultaneous operation in each of the three beds.

The aforesaid feedstock is fed at a pressure of 1045 psia through line 10 to adsorber 12 which contains as the adsorbent zeolite A having 80 equivalent percent calcium cations and 20 equivalent percent sodium cations and containing 2.6 weight-% adsorbed H2 O. Adsorber 12 is operated during this adsorption step at 92° F. The effluent from the adsorber 12 is essentially pure methane. In due course an adsorption front for each of the components H2 O, H2 S and CO2 are formed in the adsorber with H2 O front being closest to the ingress end of the bed and the CO2 front being nearest the egress end of the bed. Since in this embodiment it is the purpose to remove only the H2 S, the CO2 front is permitted to break through the egress end of the adsorber and commingle with the product methane which is in the main removed from the system through line 14. A portion of the product methane is continuously passed through line 16 to the top of adsorber 18 which at the beginning of the adsorption stroke in adsorber 12 had just finished being hot purge desorbed and contains essentially H2 S-free product methane. The adsorber is at a temperature of 500° F. The purified methane entering adsorber 18 is at a temperature of 92° F. and in its passage through adsorber 18 cools that adsorber until a temperature of 125° F. is reached. The thus heated gas leaving bed 18 is passed through line 20, furnace 22 where the temperature is raised to 550° F., and line 24 into adsorber 26 which at the beginning of the adsorption fill stroke in adsorber 12 has just completed a downward adsorption fill stroke using feedstock of the same composition as is currently being introduced through line 10. The heated purge gas from furnace 22 is injected with water through line 28 to raise the water vapor content to 0.185 mole percent. The desorbate stream from adsorber 26 which contains the H2 O and H2 S previously adsorbed is fed through line 30 to sulfur recovery unit 32. Stack gases are passed from the system through line 34 and sulfur collected from line 36. The COS content of the product methane leaving the system through line 14 is less than 8 ppm.

(b) Using the same procedure, feedstock and apparatus as set forth in part (a) above, except that the zeolite adsorbent in adsorber 12 contained less than 0.7 weight-% adsorbed H2 O, the COS content of the product methane leaving the system through line 14 is about 45 ppm.

Claims (2)

What is claimed is:
1. A cyclic process comprising the steps of:
(a) an adsorption purification stroke wherein a hydrocarbon stream containing H2 S and CO2 is contacted in the vapor phase at a temperature of from 60° F. to 120° F. with a molecular sieve adsorbent in a fixed bed to selectively adsorb H2 S and a hydrocarbon product is recovered which is substantially free of H2 S;
(b) a purge desorption stroke wherein a portion of the substantially H2 S-free hydrocarbon product recovered in step (a) is heated to above 120° F. and passed countercurrently through the adsorption bed to desorb substantially all of the adsorbate molecules selectively adsorbed in step (a) and flush same from the bed;
(c) a cool-down stroke wherein the bed is cooled to below 120° F. by the cocurrent purge therethrough of a portion of the substantially H2 S-free hydrocarbon recovered in step (a) at a temperature of from 60° F. to 120° F.;
the improvement which comprises utilizing as the said molecular sieve adsorbent a crystalline zeolite having a pore diameter of at least 5 Angstroms, at least 45 percent of the framework aluminum atoms thereof being associated with at least one species of alkaline earth metal cation having an atomic number of less than 56, and injecting into said hydrocarbon stream prior to passage through the bed in step (b) a sufficient amount of water vapor to impart a substantially uniform adsorbed water loading of from 0.7 to 3.0 weight percent to the molecular sieve adsorbent.
2. Process according to claim 1 wherein the hydrocarbon of the stream being treated is methane containing not greater than 5 mole percent H2 S from 0.5 to 55 mole percent carbon dioxide, and the molecular sieve adsorbent is the calcium cation form of zeolite A having at least 45 equivalent percent calcium cations.
US05935757 1974-07-08 1978-08-22 Suppression of COS formation in molecular sieve purification of hydrocarbon gas streams Expired - Lifetime US4329160A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US48663874 true 1974-07-08 1974-07-08
US83600177 true 1977-09-23 1977-09-23
US05935757 US4329160A (en) 1974-07-08 1978-08-22 Suppression of COS formation in molecular sieve purification of hydrocarbon gas streams

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US05935757 US4329160A (en) 1974-07-08 1978-08-22 Suppression of COS formation in molecular sieve purification of hydrocarbon gas streams

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
US83600177 Continuation-In-Part 1977-09-23 1977-09-23

Publications (1)

Publication Number Publication Date
US4329160A true US4329160A (en) 1982-05-11

Family

ID=27048755

Family Applications (1)

Application Number Title Priority Date Filing Date
US05935757 Expired - Lifetime US4329160A (en) 1974-07-08 1978-08-22 Suppression of COS formation in molecular sieve purification of hydrocarbon gas streams

Country Status (1)

Country Link
US (1) US4329160A (en)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0211560A2 (en) * 1985-08-14 1987-02-25 Imperial Chemical Industries Plc Gas purification
US20040091753A1 (en) * 2001-03-02 2004-05-13 Robert Johan Andreas Maria Terorde Process and apparatus for removing sulfur compounds from hydrocarbon streams
US6736879B2 (en) * 2002-05-01 2004-05-18 Chevron Phillips Chemical Company Lp Process to prepare low carbon disulfide containing dimethyl sulfide
FR2868338A1 (en) * 2004-03-31 2005-10-07 Ceca Sa Sa Zeolitic adsorbent composition, process for its preparation and its use for the removal of H20 and H2S content or in gas mixtures or liquids
US20060043001A1 (en) * 2004-09-01 2006-03-02 Sud-Chemie Inc. Desulfurization system and method for desulfurizing afuel stream
US20060107832A1 (en) * 2002-10-29 2006-05-25 Van De Graaf Jolinde M Removal of sulphur compounds from hydrocarbon streams using adsorbents and regeneration of the loaded adsorbents
US20060110305A1 (en) * 2002-11-28 2006-05-25 Van De Graaf Jolinde M Process for removing sulphur compounds including hydrogen sulphide and mercaptans from gas streams
US20060283780A1 (en) * 2004-09-01 2006-12-21 Sud-Chemie Inc., Desulfurization system and method for desulfurizing a fuel stream
US20070017852A1 (en) * 2005-03-08 2007-01-25 Peter Meyer Process of removal of sulphur compounds from hydrocarbon streams using adsorbents
WO2007017888A1 (en) * 2005-08-09 2007-02-15 Indian Petrochemical Corporation Limited Adsorbents for purification of c2-c3 olefins
US20070131589A1 (en) * 2004-09-01 2007-06-14 Sud-Chemie Inc. Sulfur adsorbent, desulfurization system and method for desulfurizing
US20090272675A1 (en) * 2004-09-01 2009-11-05 Sud-Chemie Inc. Desulfurization system and method for desulfurizing a fuel stream
US20120289439A1 (en) * 2010-01-07 2012-11-15 Carolus Matthias Anna Maria Mesters Process for the manufacture of sulphide compounds

Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2996558A (en) * 1957-04-17 1961-08-15 Exxon Research Engineering Co Molecular sieve separation process
US3061992A (en) * 1958-12-12 1962-11-06 George F Russell Gas treatment by adsorption
US3078640A (en) * 1959-12-18 1963-02-26 Union Carbide Corp Separation of sulfur compounds from vapor mixtures
US3078634A (en) * 1959-11-30 1963-02-26 Union Carbide Corp Sweetening and drying of natural gas
US3078641A (en) * 1959-12-31 1963-02-26 Union Carbide Corp Separation of sulfur compounds from vapor mixtures
US3416293A (en) * 1967-06-22 1968-12-17 Catalysts & Chem Inc Sulfur adsorption
US3470677A (en) * 1967-01-24 1969-10-07 Allied Chem Method of reactivating molecular sieves
US3660967A (en) * 1970-09-08 1972-05-09 Union Carbide Corp Purification of fluid streams by selective adsorption
US3751878A (en) * 1972-10-20 1973-08-14 Union Carbide Corp Bulk separation of carbon dioxide from natural gas
US3808773A (en) * 1970-12-28 1974-05-07 Linde Ag Process and apparatus for the adsorptive purification of gases

Patent Citations (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2996558A (en) * 1957-04-17 1961-08-15 Exxon Research Engineering Co Molecular sieve separation process
US3061992A (en) * 1958-12-12 1962-11-06 George F Russell Gas treatment by adsorption
US3078634A (en) * 1959-11-30 1963-02-26 Union Carbide Corp Sweetening and drying of natural gas
US3078640A (en) * 1959-12-18 1963-02-26 Union Carbide Corp Separation of sulfur compounds from vapor mixtures
US3078641A (en) * 1959-12-31 1963-02-26 Union Carbide Corp Separation of sulfur compounds from vapor mixtures
US3470677A (en) * 1967-01-24 1969-10-07 Allied Chem Method of reactivating molecular sieves
US3416293A (en) * 1967-06-22 1968-12-17 Catalysts & Chem Inc Sulfur adsorption
US3660967A (en) * 1970-09-08 1972-05-09 Union Carbide Corp Purification of fluid streams by selective adsorption
US3808773A (en) * 1970-12-28 1974-05-07 Linde Ag Process and apparatus for the adsorptive purification of gases
US3751878A (en) * 1972-10-20 1973-08-14 Union Carbide Corp Bulk separation of carbon dioxide from natural gas

Cited By (23)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0211560A3 (en) * 1985-08-14 1988-06-01 Imperial Chemical Industries Plc Gas purification
EP0211560A2 (en) * 1985-08-14 1987-02-25 Imperial Chemical Industries Plc Gas purification
US20040091753A1 (en) * 2001-03-02 2004-05-13 Robert Johan Andreas Maria Terorde Process and apparatus for removing sulfur compounds from hydrocarbon streams
US6736879B2 (en) * 2002-05-01 2004-05-18 Chevron Phillips Chemical Company Lp Process to prepare low carbon disulfide containing dimethyl sulfide
US20060107832A1 (en) * 2002-10-29 2006-05-25 Van De Graaf Jolinde M Removal of sulphur compounds from hydrocarbon streams using adsorbents and regeneration of the loaded adsorbents
US7517389B2 (en) * 2002-10-29 2009-04-14 Shell Oil Company Removal of sulphur compounds from hydrocarbon streams using adsorbents and regeneration of the loaded adsorbents
US20060110305A1 (en) * 2002-11-28 2006-05-25 Van De Graaf Jolinde M Process for removing sulphur compounds including hydrogen sulphide and mercaptans from gas streams
US7425314B2 (en) 2002-11-28 2008-09-16 Shell Oil Company Process for removing sulphur compounds including hydrogen sulphide and mercaptans from gas streams
US7825056B2 (en) 2004-03-31 2010-11-02 Ceca, S.A. Adsorbent zeolitic composition, its method of preparation and its use for removing H2O and/or CO2 and/or H2S contained in gas or liquid mixtures
WO2005094985A3 (en) * 2004-03-31 2006-01-26 Ceca Sa Zeolithic adsorbing composition, method for the preparation and the use thereof for removing de h2o and /or co2 and/or h2s contained in gas or liquid mixtures
WO2005094985A2 (en) * 2004-03-31 2005-10-13 Ceca S.A. Zeolithic adsorbing composition, method for the preparation and the use thereof for removing de h2o and /or co2 and/or h2s contained in gas or liquid mixtures
FR2868338A1 (en) * 2004-03-31 2005-10-07 Ceca Sa Sa Zeolitic adsorbent composition, process for its preparation and its use for the removal of H20 and H2S content or in gas mixtures or liquids
CN1960790B (en) 2004-03-31 2011-12-14 策卡有限公司 Zeolite adsorbent compositions, their preparation and their use for removal of H gas or liquid mixture contained <sub> 2 </ sub> O and / or CO <sub> 2 </ sub> and / or H <sub> 2 use </ sub> S of
US20070214959A1 (en) * 2004-03-31 2007-09-20 Remi Le Bec Adsorbent Zeolitic Composition, Its Method Of Preparation And Its Use For Removing H2o And/Or Co2 And/Or H2s Contained In Gas Or Liquid Mixtures
US8323603B2 (en) 2004-09-01 2012-12-04 Sud-Chemie Inc. Desulfurization system and method for desulfurizing a fuel stream
US20070131589A1 (en) * 2004-09-01 2007-06-14 Sud-Chemie Inc. Sulfur adsorbent, desulfurization system and method for desulfurizing
US20060283780A1 (en) * 2004-09-01 2006-12-21 Sud-Chemie Inc., Desulfurization system and method for desulfurizing a fuel stream
US20090272675A1 (en) * 2004-09-01 2009-11-05 Sud-Chemie Inc. Desulfurization system and method for desulfurizing a fuel stream
US7780846B2 (en) 2004-09-01 2010-08-24 Sud-Chemie Inc. Sulfur adsorbent, desulfurization system and method for desulfurizing
US20060043001A1 (en) * 2004-09-01 2006-03-02 Sud-Chemie Inc. Desulfurization system and method for desulfurizing afuel stream
US20070017852A1 (en) * 2005-03-08 2007-01-25 Peter Meyer Process of removal of sulphur compounds from hydrocarbon streams using adsorbents
WO2007017888A1 (en) * 2005-08-09 2007-02-15 Indian Petrochemical Corporation Limited Adsorbents for purification of c2-c3 olefins
US20120289439A1 (en) * 2010-01-07 2012-11-15 Carolus Matthias Anna Maria Mesters Process for the manufacture of sulphide compounds

Similar Documents

Publication Publication Date Title
US3176444A (en) Adsorption separation process
US4498991A (en) Serial flow continuous separation process
US5711926A (en) Pressure swing adsorption system for ammonia synthesis
US5112590A (en) Separation of gas mixtures including hydrogen
US5531808A (en) Removal of carbon dioxide from gas streams
US4478721A (en) High efficiency continuous separation process
US5234472A (en) Separation of gas mixtures including hydrogen
US5133785A (en) Separation of multicomponent gas mixtures by selective adsorption
US5203888A (en) Pressure swing adsorption process with multiple desorption steps
US3594983A (en) Gas-treating process and system
US2992703A (en) Separation of carbon dioxide from ammonia
US3102013A (en) Heatless fractionation utilizing zones in series and parallel
US3797201A (en) Absorption process for gas separation
US20020009404A1 (en) Molecular sieve adsorbent-catalyst for sulfur compound contaminated gas and liquid streams and process for its use
US4769047A (en) Process for the production of ethylene oxide
US4512780A (en) Pressure swing adsorption with intermediate product recovery
US6444012B1 (en) Selective removal of nitrogen from natural gas by pressure swing adsorption
US4376640A (en) Repressurization of pressure swing adsorption system
US6497750B2 (en) Pressure swing adsorption process
US4978439A (en) Desulphurisation using solid sorbents
Jayaraman et al. Clinoptilolites for nitrogen/methane separation
US3225516A (en) Method and apparatus for purifying gaseous mixtures by cyclic adsorption
US6610124B1 (en) Heavy hydrocarbon recovery from pressure swing adsorption unit tail gas
US5084075A (en) Vacuum swing adsorption process for production of 95+% n2 from ambient air
US4971606A (en) Closed-loop thermal regeneration of adsorbents containing reactive adsorbates

Legal Events

Date Code Title Description
AS Assignment

Owner name: MORGAN GUARANTY TRUST COMPANY OF NEW YORK, AND MOR

Free format text: MORTGAGE;ASSIGNORS:UNION CARBIDE CORPORATION, A CORP.,;STP CORPORATION, A CORP. OF DE.,;UNION CARBIDE AGRICULTURAL PRODUCTS CO., INC., A CORP. OF PA.,;AND OTHERS;REEL/FRAME:004547/0001

Effective date: 19860106

AS Assignment

Owner name: UNION CARBIDE CORPORATION,

Free format text: RELEASED BY SECURED PARTY;ASSIGNOR:MORGAN BANK (DELAWARE) AS COLLATERAL AGENT;REEL/FRAME:004665/0131

Effective date: 19860925

AS Assignment

Owner name: UOP, DES PLAINES, IL., A NY GENERAL PARTNERSHIP

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:KATALISTIKS INTERNATIONAL, INC.;REEL/FRAME:004994/0001

Effective date: 19880916

Owner name: KATALISTIKS INTERNATIONAL, INC., DANBURY, CT, A CO

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:UNION CARBIDE CORPORATION;REEL/FRAME:004998/0636

Effective date: 19880916

Owner name: KATALISTIKS INTERNATIONAL, INC., CONNECTICUT

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:UNION CARBIDE CORPORATION;REEL/FRAME:004998/0636

Effective date: 19880916